Superstorm Sandy and the importance of polar orbiting satellites in forecasting
On the 23rd of October, the 18th named storm of the 2012 Atlantic hurricane season, Tropical Storm Sandy, was born in the Central Caribbean. As is common for late-season storms in the Caribbean, Sandy moved northwards across Cuba. The official forecasts from the National Hurricane Center issued on October 23 called for Sandy to turn to the northeast after crossing Cuba, and head into the Central Atlantic. This forecast was based on the output from five of our top six computer models, which all predicted that an upper-level low pressure system in the Central Atlantic would be strong enough to pull Sandy northeastwards. However, the global weather forecast model run by the European Center for Medium-Range Weather Forecasts (ECMWF) showed a disturbing possibility: the upper-level low pressure system in the Central Atlantic would not be strong enough to turn Sandy to the northeast. The hurricane would instead get caught up in the flow associated with a trough of low pressure approaching the U.S. East Coast, and Sandy would get slung into New York or New Jersey on October 29. While the ECMWF model was the best performing model for tracking Atlantic hurricanes in both 2010 and 2011, and had done very well again so far in 2012, the American GFS model had outperformed the ECMWF model several times during the 2012 season. NHC elected to discount the ECMWF forecast for Sandy as an outlier, and went with the forecast from the GFS and other models. By October 25, it was clear that the ECMWF model had the right idea all along. More models were now showing the turn towards New York, and the official NHC forecast now called for Sandy to make landfall in New York or New Jersey on October 29. The ECMWF model's early forecast of a track for Sandy into the Northeast was critical for allowing additional time for residents to prepare for arrival of the devastating storm. So what enabled the ECMWF model to make such an excellent forecast for Sandy, six days in advance?
Figure 1. This image uses the model output from the ECMWF experiment, showing where Sandy was predicted to be located five-days out with the normal satellite data inputs into the model (left) and without any polar-orbiting satellite data (right). Both position and intensity forecasts were affected--Sandy stays out to sea without the polar-orbiting satellite data, and the closer isobar lines encircling the storm also imply a more organized and stronger system. Image credit: NOAA.
Polar satellite data: a key to ECMWF model success
The ECWMF has a very sophisticated technique called "4-D Var" for gathering all the current weather data over the Earth and putting the data on a 3-dimensional grid that is then used as the initial "reality" of the current weather for the model to use for its forecast. The old expression, "garbage in, garbage out" is a truism for weather forecast models. If you don't properly characterize the initial state of the atmosphere, the errors you start off with will grow and give a lower-quality forecast. Data from geostationary satellites, which sit continuously at one spot above the globe, are easy to assimilate, and all the models use this data. However, the ECMWF model's superior technique used to assimilate the initial data allows inclusion of data from a large number of polar-orbiting satellites, which the other models cannot do as well. Polar-orbiting satellites orbit Earth at an altitude of 540 miles twice per day, circling from pole to pole. Their data is difficult to use, since the it is only available twice per day at each spot on the Earth, and the time of availability is different for each location. According to an email I received from Jean-Noël Thépaut, the chief of the Data Division of the Research Department at the European Center for Medium-Range Weather Forecasts, the ECMWF model uses data from at least fourteen polar orbiting satellites: N-15, N-19, N-19, N-17 (ozone SBUV instrument only), Metop-A, AQUA, NPP (ATMS instrument only), AURA (ozone OMI data only), F-17, TRMM (TMI data), COSMIC, GRACE-A, TERRASAR, and the GPSRO data on top of METOP-GRAS. The data of most importance is the data collected in the infrared and microwave wavelengths, as well as atmospheric density data obtained via GPS radio occultation (as a polar orbiting satellite goes over the horizon, the GPS signals from the satellite get bent by Earth's atmosphere, with the amount of bending proportional to the density of the atmosphere. This GPS Radio Occultation data is gathered from eight polar orbiting satellites, and fed into both the ECMWF and GFS models.) You can find a nice summary of the impacts of polar orbiting satellite data on weather prediction models at this link.)
Figure 2. Forecast track error for four of our top models used to predict Hurricane Sandy, for their runs that began at 00Z October 25, 2012. By this time, the GFDL model had joined the ECMWF in predicting that Sandy would make landfall in Southern New Jersey in five days. The GFS and HWRF models made good 1 - 3 day forecasts, but failed to anticipate Sandy's north-northwestward turn towards the U.S. coast. Image credit: Morris Bender, NOAA/GFDL.
As originally reported by the Washington Post's Capital Weather Gang, then confirmed in a NOAA press release, a study done by ECMWF research scientist Tony McNally found that if the ECMWF model did not have all of the data from the fourteen polar orbiting satellites, the five-day forecast of the model for Hurricane Sandy would have shown Sandy missing the Northeast U.S. This brings up a concern, since the U.S. polar orbiting satellite program is behind schedule. As explained by Andrew Freedman of Climate Central, the program is plagued by mismanagement, billions in cost overruns, and technical development challenges. The next polar orbiting satellite is not scheduled to be launched until 2017, and one or more of the existing polar orbiting satellites are expected to fail before then. This will result in a degradation of our ability to observe and predict the weather, and may result in poorer forecasts for storms like Hurricane Sandy. Given that the ECMWF model used data from fourteen polar orbiting satellites, the failure of just one satellite may not have made a significant difference in its forecast for Sandy. But if we lose several of these key satellites by 2017, our hurricane forecasts in 2017 may be worse than they were in 2012. To figure out how to cope with the loss of satellite-derived data, NOAA is conducting a Gap Risk Study that seeks ideas from researchers and the public on how NOAA can preserve the quality of its weather model forecasts in the event of the failure of one or more polar orbiting satellites in the coming years.
Figure 3. A tanker rests on the southern shore after being swept onto land by a storm surge due to Superstorm Sandy, Friday, Nov. 2, 2012, in the Staten Island borough of New York. (AP Photo/ John Minchillo)
Links
Eric Berger of the Houston Chronicle has an interview with Jean-Noël Thépaut, chief of the Data Division of the Research Department at the European Center for Medium-Range Weather Forecasts, on why the European model did so well with Hurricane Sandy.
Jeff Masters
Reader Comments
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I have a hard time believing that
A United Nations report says nearly a million people are in need of food assistance in the south-eastern Philippines.
It says they are still suffering the effects of being displaced a month after powerful typhoon Bopha devastated the region.
The typhoon has killed more than 1,000 people and left more than 800 others missing.
Shirley Escalante reports that Philippines social welfare officials and the World Food Program say food packs have been distributed to 238,000 people, and school feeding programs will be launched to meet the needs of those requiring assistance.
The United Nations Office for the Coordination of Humanitarian Affairs reports only a fifth of the UN's appeal for $US65 million in aid has been met.
The governor of the Philippines province of Albay, Joey Salceda, says countries whose greenhouse emissions caused climate change should bear a larger responsibility for its victims.
The province is regularly hit by storms and he has decried the slow international response.
© ABC 2013
Brutal Cold Waves Could be Heading for the U.S.
Link
"...According to Long Range Weather Expert Paul Pastelok, "The early indications are that the initial thrust of the brutal cold will be directed over the Northwest, northern Rockies or northern Plains first, with subsequent waves reaching farther east..."
Yo! Weather Gods! Give it to the east coasters... they keep asking for snow!
So... to you, realistically is this glass half full or half empty???
To me it's half full. Btw, I don't expect an answer from you. Just curious, that's all.
Anyways, Currently 22.3*C(72.1*F)
Updated at 02:00 EDT
and headed up already. Wish us all luck. Goodnight.
We'll see. The Houston-Galveston discussion this morning:
MODELS DIVERGE A BIT ON WEDNESDAY. THE GLOBAL MODELS CONTINUE WITH HIGH RAIN CHANCES BUT THE TEXAS TECH 3 KM WRF AND THE NAM FOCUS MORE OF THE PRECIP OVER CENTRAL TEXAS WITH LESS ACTIVITY OVER SE TEXAS. THERE ARE TIMING DIFFERENCES BETWEEN THE FASTER GFS... SLOWER CANADIAN WITH THE ECMWF KIND OF IN BETWEEN. THE 00Z GFS IS MORE AGGRESSIVE WITH DRY SLOTTING THE AREA ON WEDNESDAY AFTN ENDING THE PRECIP MUCH SOONER THAN THE OTHER MODELS. THE NAM NEVER BRINGS THE PACIFIC FRONT THROUGH THE REGION BY 18Z THURSDAY. THE ECMWF HAS BACKED OFF A BIT ON THE STRENGTH OF THE UPPER LEVEL DIVERGENCE BUT THE POSITION OF THE UPPER LOW WOULD SUGGEST STRONG DIVERGENCE SHOULD CONTINUE. WISH THE MODELS WERE IN BETTER AGREEMENT FOR WEDNESDAY AND IT IS NOT OUT OF THE REALM OF POSSIBILITIES THAT SE TX COULD GET DRY SLOTTED BY 18Z IF THE 00Z GFS IS CORRECT.
Just posted on my blog..
I'm trying to get better at it..
It's titled:
2012--Year in Pictures--
Please stop in and leave comments so I can keep getting better on my posts..
TIA.. :)
Optimism might be interpreted as what some people call mindfulness. Seems that there is a perverse slant to this.
Wisdom from Psychopaths
It comes from a book titled The Wisdom of Psychopaths: What Saints, Spies, and Serial Killers Can Teach Us About Success.
A burnt bulding and eaten children are not the same thing. Mother Nature is 100 % callus.
Funny though how Koala's remain a viable species.
Rain is not as uniform as you seem to think. The totals can drop off rather sharply.
At any rate, if someone brought me a glass tumbler just like that in the photo and asked me how much it held, I'd answer, "It's about half full of water, and half full of air." But context also matters. If, for instance, it were a full drink I'd just paid for, I'd complain to the bartender that it was half empty. But if I were the bar's owner and saw my bartender give that to a customer who'd only paid for a shot of vodka, I'd complain that it was half full.
And that's the point of this exercise, I guess. In short, there are few absolutes in life. It's packed with ambiguities; grey areas abound. And, as I said, I'm a realist. That means I would call it as honestly as I see it--and that could change numerous times over the course of a day. Or an hour. Or a minute...
I'm aware of that
I get what you are getting at LOL .. I dont want to bring the subject up in a good mood today but I never said it does not exist.. But I enjoy your posts they make me think !!
To me, averted vision produces an optical illusion where the bottom half of the glass is wider than the top. Therefore, when I drink from the glass, it will be completely empty.
South Australia could really use some of that water ... still can't believe they're getting 40C temperatures in Tasmania!
May I comment on this? Realistically, what I see, it is that you have twice as much glass as what is necessary to contain the water. ... OK, back to your regularly scheduled program.
Is debating a problem?
My own question: why is polite dialog considered going "at it again" or "flexing arms"? And a followup question: why don't those who are bothered by it simply place me (and/or Tomball) on ignore? It's quite simple, really... ;-)
If that was Lindsay Lohan's glass I'd say 80 proof and def completely empty :-)
Happy Monday all. Hoping this rainmaker pans out here in the South.
Nice, do I detect a mechanical engineer? I know a few...
At the conclusion of each hurricane season NOAA conducts a review of operations and considers options to enhance its products and services. Following the annual post-season NOAA Hurricane Meeting that took place in November 2012, the NWS will be exploring two proposals that, if adopted, would result in some changes to National Weather Service (NWS) products and warnings. The first of these proposed changes originates from the unique situation posed by Hurricane Sandy; it would give the National Hurricane Center (NHC) the option to continue issuing formal advisories on post-tropical cyclones as long as those systems pose a significant threat to life and property, and it would give the NWS the option to keep hurricane and tropical storm watches and warnings in place for those systems. The second proposal would set a target date of 2015 for NOAA to implement explicit Storm Surge Watches and Warnings, a goal NOAA has been working toward for several years. The NWS Office of Climate, Weather, and Water Services (OCWWS) will review these two proposals in conjunction with a Hurricane Sandy service assessment and the NWS looks forward to continued engagement with its partners and users about these proposals.
See more: http://www.nhc.noaa.gov/news/20130107_pa_hurricane Program.pdf
A COLD FRONT DRAPED ACROSS THE TREASURE COAST AND LAKE OKEECHOBEE
THIS MORNING WILL CONTINUE TO PUSH SOUTH OF THE AREA THIS AFTERNOON.
THE FRONT WILL NOT SCOUR OUT THE MOISTURE SO EXPECT MORE CLOUDS THAN
SUN WITH TEMPERATURES REACHING THE UPPER 60S OVER LAKE AND VOLUSIA
COUNTIES TO THE MID 70S TREASURE COAST. THESE TEMPERATURES ARE
ACTUALLY VERY CLOSE TO NORMAL FOR THIS TIME OF YEAR BUT BREEZY
NORTHEAST WINDS DEVELOPING BEHIND THE FRONT...ESPECIALLY NEAR THE
COAST...WILL ADD A CHILL. THE BEST CHANCE FOR SHOWERS WILL OCCUR
FROM OKEECHOBEE TO THE TREASURE COAST BUT ISOLATED SHOWER OR SPRINKLE
MAY OCCUR JUST ABOUT ANYWHERE THROUGH MID DAY. ADDITIONAL ISOLATED
SHOWERS ARE EXPECTED TO DEVELOP OFFSHORE VOLUSIA AND BREVARD COUNTIES
THIS AFTERNOON SOME OF WHICH MAY REACH THE COAST LATE IN THE DAY.
&&
394.39ppm
Atmospheric CO2 for December 2012
Preliminary data dated January 3, 2013
12Z GFS is way more aggressive with the rain totals and looks quite similar in result to the 00Z CMC.
12Z GFS for Thursday 12Z (@ 72 hours)
00Z CMC for Thursday 12Z (@ 84 hours)
It's just that when it should be cold it should be cold.Not highs in the 60's and 70's.
National Oceanic and Atmospheric Administration
National Climatic Data Center
How do we know the Earth's climate is warming?
Thousands of land and ocean temperature measurements are recorded each day around the globe. This includes measurements from climate reference stations, weather stations, ships, buoys and autonomous gliders in the oceans. These surface measurements are also supplemented with satellite measurements. These measurements are processed, examined for random and systematic errors, and then finally combined to produce a time series of global average temperature change.
A number of agencies around the world have produced datasets of global-scale changes in surface temperature using different techniques to process the data and remove measurement errors that could lead to false interpretations of temperature trends.
The warming trend that is apparent in all of the independent methods of calculating global temperature change is also confirmed by other independent observations, such as the melting of mountain glaciers on every continent, reductions in the extent of snow cover, earlier blooming of plants in spring, a shorter ice season on lakes and rivers, ocean heat content, reduced arctic sea ice, and rising sea levels.
Global Climate Change Indicators
National Oceanic and Atmospheric Administration
National Climatic Data Center
How do we know the Earth's climate is warming?
Thousands of land and ocean temperature measurements are recorded each day around the globe. This includes measurements from climate reference stations, weather stations, ships, buoys and autonomous gliders in the oceans. These surface measurements are also supplemented with satellite measurements. These measurements are processed, examined for random and systematic errors, and then finally combined to produce a time series of global average temperature change.
A number of agencies around the world have produced datasets of global-scale changes in surface temperature using different techniques to process the data and remove measurement errors that could lead to false interpretations of temperature trends.
The warming trend that is apparent in all of the independent methods of calculating global temperature change is also confirmed by other independent observations, such as the melting of mountain glaciers on every continent, reductions in the extent of snow cover, earlier blooming of plants in spring, a shorter ice season on lakes and rivers, ocean heat content, reduced arctic sea ice, and rising sea levels.
Global annual average temperature measured over land and oceans. Red bars indicate temperatures above and blue bars indicate temperatures below the 1901-2000 average temperature. The black line shows atmospheric carbon dioxide concentration in parts per million.
Global average temperature is one of the most-cited indicators of global climate change, and shows an increase of approximately 1.4°F since the early 20th Century. The global surface temperature is based on air temperature data over land and sea-surface temperatures observed from ships, buoys and satellites. There is a clear long-term global warming trend, while each individual year does not always show a temperature increase relative to the previous year, and some years show greater changes than others. These year-to-year fluctuations in temperature are due to natural processes, such as the effects of El Ninos, La Ninas, and the eruption of large volcanoes. Notably, the 20 warmest years have all occurred since 1981, and the 10 warmest have all occurred in the past 12 years.
I know what your saying Tomball..
But realistically should we turn a blind eye to the subject?
Been in there several times and have learned alot..
don't post in there however as I'm still learning on the subject and it wouldn't be productive..
By the way I see you post in there quite often..
No, I am not an engineer of any type. I am, however, mechanically inclined. You can show me any piece of machinery and I can tell you how you can break it. :-)
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